Shirley Bassey serenades the waiting press
The 68-year-old actress married theatre designer Percy Gibson at Claridges Hotel in London on Sunday.
About 180 guests attended the ceremony, where the dress code specified "glamorous". Hundreds of fans waited outside.
Many of them were celebrities from an older generation, including television presenter Cilla Black, composer Tim Rice and James Bond actor Roger Moore.
Singer Shirley Bassey delighted hundreds of well-wishers by turning up in a scarlet gown with matching beret and fur.
Asked if she was looking forward to the wedding, Bassey replied: "Of course I am. Why do you think I look like Little Red Riding Hood?"
'Bootylicious'
Cilla Black - accompanied by stage and TV actor Christopher Biggins - said: "I haven't been to a wedding in ages. I am excited.
"I went out to dinner with the lucky man and he's gorgeous. He's bootylicious."
David Furnish - the partner of Sir Elton John - was also at the ceremony, as were Collins' three grown-up children.
But neither the bride nor groom appeared in public - the couple had signed a deal with a celebrity magazine.
After the 45-minute service, spokeswoman Stella Wilson emerged to tell reporters: "Joan Collins is now Mrs Gibson.
"It was a very emotional ceremony. They exchanged traditional vows. We all cried, including Joan."
Ms Wilson added the actress was wearing a full-length lilac silk gown with a train.
The couple met when Collins was starring in the play Love Letters, which was touring the US.
But love did not blossom until Gibson helped her edit her latest novel, Star Quality.
Past husbands
Collins first married in 1952, to actor Maxwell Reed, but they divorced five years later.
In 1963, she wed actor, singer and composer Anthony Newley, with whom she had daughter Tara and son Sacha. That marriage lasted eight years.
Music and film producer Ron Kass was next in 1972, and they had daughter Katy, before divorcing in 1983 after he became a drug addict.
Marriage number four was in 1985 to Swedish singer Peter Holm, but that lasted only a year.
Collins' private life has tended to overshadow her career - she made her film debut as a beauty contest entrant in 1951's Lady Godiva Rides Again, but came to Hollywood after starring as a femme fatale in Howard Hawks' 1955 Egyptian epic Land of the Pharaohs.
But her career dipped during the late 1960s and 1970s - which ended with her starring in sexually suggestive films The Stud and The Bitch, both based on books by her sister Jackie.
TV soap Dynasty revived her career in the 1980s, and stage roles followed in the 1990s. More recently she has played a 1950s actress in the London stage production Over the Moon.